Integrated Pest Management of Insect Pests of Rapeseed

Rothamsted Research where knowledge grows

Integrated Pest Management of insect pests of rapeseed

Sam Cook Rothamsted Research, UK Rothamsted Research where knowledge grows Integrated Pest Management of insect pests of rapeseed Dedication: Prof Lloyd Dosdall

1952 - June 12 2014 Insects love rapeseed! Rapeseed is important for farmland biodiversity

Rapeseed is important to a wide variety of invertebrates

Surveys in UK using a range of techniques…

…collected 151 species + c. 40 additional groups id to genus or higher taxonomic rank

Skellern & Cook in prep Rapeseed is important for farmland biodiversity

Rapeseed crops support populations of bees, butterflies & other pollinators, natural enemies of crop pests, detritivores & invertebrates used as food resources for farmland birds

British Ornithologists Union

Skellern & Cook in prep Rapeseed is important for farmland biodiversity

Need to better manage the crop to harness the biodiversity potential of the crop – towards ‘sustainable intensification’

Talk outline: Summarise the insect pests of rapeseed Ecological approaches to pest management via IPM

Rapeseed grown ‘worldwide’… Focus on winter rapeseed Brassica napus in Europe!

What are the insect pests of rapeseed?

Cabbage stem flea beetle (Psylliodes chrysocephala) What are the insect pests of rapeseed?

Peach potato aphid (Myzus persicae) What are the insect pests of rapeseed?

Rape stem weevil (Ceutorhynchus napi) What are the insect pests of rapeseed?

Rape winter stem weevil (Ceutorhynchus picitarsis) What are the insect pests of rapeseed?

Pollen beetle (Meligethes / Brassicogethes aeneus) What are the insect pests of rapeseed?

Cabbage root fly (Delia radicum) What are the insect pests of rapeseed?

Mealy aphid (Brevicoryne brassicae) What are the insect pests of rapeseed?

Cabbage seed weevil / seedpod weevil (Ceutorhynchus obstrictus /assimilis )

What are the insect pests of rapeseed?

Brassica pod midge (Dasineura brassicae) What are the insect pests of rapeseed?

‘Minor’ pests: Turnip sawfly (Athalia rosae) What are the insect pests of rapeseed?

Spring crop pests Cabbage stem weevil (Ceutorhynchus pallidactylus) What are the insect pests of rapeseed?

Spring crop pests Flea beetles (Phyllotreta cruciferae) What are the insect pests of rapeseed?

Spring crop pests Flea beetles (Phyllotreta cruciferae, P. striolata, P. nemorum) What are the insect pests of rapeseed?

Diamondback moth (Plutella xylostella) What are the insect pests of rapeseed?

Lygus bugs (Lygus sp.) What are the insect pests of rapeseed?

Bertha armyworm (Mamestra configurata) Cabbage stem flea beetle (Psylliodes chrysocephala)

• Most widely distributed stem-mining pest in Europe; also recorded from Middle East, Asia, North Africa, Canada

CABI

Cabbage stem flea beetle (Psylliodes chrysocephala) Late Aug- Oct Adults move into new crop, mate Life cycle : univoltine feed on leaves causing ‘shot- holing Aug - Feb July – Sept Eggs laid at base Aestivate in sheltered of plant when areas warm & humid

Late Aug – May-July March Adults emerge, Larvae feed in feed on leaves, leaf petioles, 3rd pods instars feed in stem Dec – May Larvae drop to the ground ; Pupate in the soil for c. 3 months Cabbage stem flea beetle (Psylliodes chrysocephala)

Damage

• Adult feeding damage may threaten establishment (100% crop loss)

• Larvae cause loss of vigour, stem wilting, delayed flowering, stem collapse; increased risk to frost and disease

Dewar Crop Protection Cabbage stem flea beetle (Psylliodes chrysocephala)

• Adult control via neonicotinoid seed treatments since 1990s

• On 1/12/13 a 2-year restriction on the use of the neonicotinoids: clothianidin, imidacloprid and thiamethoxam, was enforced by the European Commission.

• The 2014 winter crop was the first for which neonicotinoid seed treatments were not available to protect plants during emergence and establishment Cabbage stem flea beetle (Psylliodes chrysocephala)

October 2013 (before the ban), Suffolk 2013 UK

Untreated Cruiser-treated

Dewar Crop Protection Cabbage stem flea beetle (Psylliodes chrysocephala)

• In autumn 2014 Pyrethroid sprays become the main (only?) control option…. • BUT pyrethroid resistance confirmed in Germany Zimmer et al., 2014 PBP 108:1-7

• …and widespread in UK (Sept

2014) AHDB Project 214–0019

Cabbage stem flea beetle (Psylliodes chrysocephala)

What happened in 2014? Cabbage stem flea beetle (Psylliodes chrysocephala)

What happened in 2014? • Pyrethroids were repeatedly applied! (What effect on non-targets?!) Crop sprayed: 3x vs 6x

Cabbage stem flea beetle (Psylliodes chrysocephala)

What happened in 2014? • Pyrethroids were repeatedly applied! (What effect on non-targets?!)

• By 1 December total crop losses due to adult feeding were c. 5% c. 5% of the national crop (AHDB survey).

• Strong regional variations : SE and E worst hit with c. 15% crops showing damage above adult control threshold levels

• Highest larval populations on record (Fera)

• AHDB larval survey in SE found 11 /14 sites above larval treatment thresholds; 1 site 25 larva/plant!!

• Many farmers won’t grow OSR next season 

Green peach aphid (Myzus persicae)

Distribution

• Worldwide!

CABI Green peach aphid (Myzus persicae)

Life cycle : multivoltine

Peach-potato aphid (Myzus persicae)

Damage • Feeding damage by adults and nymphs economically minor • Virus vector – Turnip yellows virus (TuYV) • Can reduce yield by c. 30% • Winged aphids can infect a crop from emergence – Oct (or Dec. if mild) • Becoming increased threat since revocation of neonicotinoid seed treatments • C. 70% of UK Myzus population infected • Resistance to pyrethroids widespread in UK and Europe; also resistance to pirimicarb; Dewar Crop Protection neonicotinoid resistance in S. Europe…. Pymetrozine only viable alternative (timing crucial)

Rape Stem Weevil (Ceutorhynchus napi)

Distribution • Central and southern Europe • unconfirmed reports in N. America • NOT yet present in northern Europe (UK)

Rape Stem Weevil (Ceutorhynchus napi)

Life cycle: univoltine Feb-March Adults migrate to crops

June-March March-April Single egg laid into stem Adults overwinter pith close to growing tip in earthen of plant; eggs hatch chambers within 1-2 weeks

May-June April—May Larvae drop to the Larvae feed within ground; pupate in soil stem for 3-5 weeks Rape Stem Weevil (Ceutorhynchus napi)

Feb-March Adults migrate to crops

June-March March-April Single egg laid into stem Adults overwinter pith close to growing tip in earthen of plant; eggs hatch chambers within 1-2 weeks

May-June April—May Larvae drop to the Larvae feed within ground; pupate in soil stem for 3-5 weeks INRA Rape Stem Weevil (Ceutorhynchus napi)

Feb-March Adults migrate to crops

June-March March-April Single egg laid into stem Adults overwinter pith close to growing tip in earthen of plant; eggs hatch chambers within 1-2 weeks

May-June April—May Larvae drop to the Larvae feed within ground; pupate in soil stem for 3-5 weeks Rape Stem Weevil (Ceutorhynchus napi)

Feb-March Adults migrate to crops

June-March March-April Single egg laid into stem Adults overwinter pith close to growing tip in earthen of plant; eggs hatch chambers within 1-2 weeks

May-June April—May Larvae drop to the Larvae feed within ground; pupate in soil stem for 3-5 weeks Rape Stem Weevil (Ceutorhynchus napi)

• Adult feeding causes little damage

• Deposition of eggs may cause distortion of plant

• Larval tunnelling causes further damage + ‘stem bursting’

• Increases susceptibility to fungal Ivan Juran pathogens

• Yield losses c. 50% INRA Pollen beetle (Meligethes aeneus)

• Brassicogethes aeneus (Audisio 2009)

Distribution • Europe • Asia: Afghanistan, Jordan, Mongolia, Turkey • N. Africa: Algeria, Morocco, Tunisia • N. America: Canada, Mexico, USA

CABI Pollen beetle (Meligethes aeneus)

Life Cycle: univoltine

Pollen beetle (Meligethes aeneus)

Damage

• Adult feeding damage at bud stage causes abscission ‘blind stalks’ • Pyrethroid resistance widespread across Untreated vs. treated Europe • Loss of control resulted in complete loss of 30,000ha (€22-25 M) in Germany 2006 • Indoxacarb, neonicotinoids (thiacloprid acetamiprid) & Pymetrozine currently viable alternatives Pollen beetle (Meligethes aeneus)

Damage

• Adult feeding damage at bud stage causes abscission ‘blind stalks’ • Pyrethroid resistance widespread across Europe • Loss of control resulted in complete loss of 30,000ha (€22-25 M) in Germany 2006 • Indoxacarb, neonicotinoids (thiacloprid acetamiprid) & Pymetrozine currently viable alternatives Cabbage Seed Weevil (Ceutorhynchus obstrictus )

Syn. C. assimilis Distribution

• Europe • Russia • Asia Minor • N. America (Canada)

CABI Cabbage Seed Weevil (Ceutorhynchus obstrictus )

May-June Life cycle: univoltine Adults emerge and migrate to OSR crops; feed, mate Mid May-July Sept – May Lay single egg into Adults overwinter in pods leaf litter in field Hatch 1-2 weeks margins & woodland Mid May- Aug Late July-Aug Larvae feed New generation on seeds 2- emerge; feed on 5 weeks Brassicas for 1-2 weeks July-Aug 3rd instars chew hole in pod, drop to ground to pupate in the soil Cabbage Seed Weevil (Ceutorhynchus obstrictus )

Damage

• Adults cause little direct damage but punctures in pod facilitates oviposition by brassica pod midge and increases risk of fungal infection by Phoma lingam (Leptosphaeria maculans)

• Yield loss through larval feeding on seeds: each larva consumes c. 5 seeds ; yield loss c. 20% (50% in N. America) Brassica pod midge (Dasineura brassicae)

Distribution

• Europe • N. Africa: Morocco

CABI Brassica pod midge (Dasineura brassicae)

Life Cycle: multivoltine

May-July Adults emerge; mate; ♂ die

Overwinter as larvae in ♀ migrate to OSR crops ; lay c. cocoons 20 eggs per pod (diapause can last for 5 Hatch in 3-4 d years)

% pupate immediately 2-3 weeks

Pods split; larvae Larvae feed on drop to soil ; spin pod wall; 3 larval cocoon instars Integrated Pest Management (IPM) of insect pests of rapeseed

Integrated Pest Management (IPM) of insect pests of rapeseed

• IPM is an effective and environmentally sensitive approach to pest management that relies on a combination practices (including the judicious use of pesticides)

• 4 usual steps in IPM programmes: 1. Set action threshold 2. Monitor pest density & assess risk 3. Prevention – cultural methods e.g. crop rotation, use of pest- resistant cultivars, semiochemical e.g. pheromone repellents, habitat diversification intercropping, trap cropping 4. Control – mechanical (e.g. trapping), biological, conservation biocontrol, botanical insecticides, synthetic pesticides 1. Set Action Thresholds

Action (economic) thresholds refer to the number of pests or level of pest damage above which require control measures. This is done to prevent damage from exceeding tolerable levels (EIL; cost of damage ≥ cost of control)

1. Set Action Thresholds

Based on: Pest biology Effects of damage on yield Response of pests to insecticides

Expressed as: Number of pests per plant or per unit area of crop Amount of damage seen on plants

1. Set Action Thresholds

• Defined for each pest species Pest UK threshold Germany Poland CSFB 25% leaf 5 larvae 10% leaf area 3-5 1/m plant - area eaten /plant eaten larvae/plant row

Peach-potato As soon as detected in aphid crop Rape stem NA 10 weevils/trap in 3d 10 weevils 2-4/25 weevil /trap in 3d plants

pollen beetle 15 adults / plant (5 for 3-4 adults/plant GS 50-51; 7-8 GS 1 adult/plant GS 50-51; backward crops) * to 2012 52-53 (3-4 on backward crops; 3 - 5 GS 52 -59 >8 GS 55-59 (>4) Cabbage seed 0.5 adults/plant in north; 0.5-1 adult / plant 4/25 plants with weevils weevil 1/plant elsewhere

Pod midge Treat for cabbage seed weevil 1. Set Action Thresholds

• Defined for each pest species; vary from country-country Pest UK threshold Germany Poland CSFB 25% leaf 5 larvae 10% leaf area 3-5 1/m plant - area eaten /plant eaten larvae/plant row

Peach-potato As soon as detected in As soon as detected in crop 2 aphid colonies/m2 at aphid crop crop edge Rape stem NA 10 weevils/trap in 3d 10 weevils 2-4/25 weevil /trap in 3d plants

Pod midge Treat for cabbage seed Treat for cabbage seed Treat for cabbage seed weevil weevil weevil

1. Set Action Thresholds

• Defined for each pest species; vary from country-country

• Why?

• Due to variations in climate? husbandry (cv. planting density, fertilizers)? landscape?

• Very few have been experimentally validated!

1. Set Action Thresholds

E.g. Revaluation of threshold for pollen beetle (UK) AHDB Project 495 (Ellis & Berry)

Previous to 2012 UK threshold 15 beetles/plant or 5 for backward crops (GS 50-61) • Logic: calculate the number of flowers that can be lost by plants to pollen beetles and still produce maximum yield • The number of ‘excess flowers’ could be predicted by # plants/m2 at the bud stage. Crops with fewer plants/m2 had more excess flowers than more dense crops • Pollen beetle threshold is negatively related to plants/m2 • 1 beetle damages c. 9 buds

1. Set Action Thresholds

Threshold for pollen beetle (UK) now based on plant density

2. Monitor pest density & assess risk

• Monitoring is necessary to determine the level of pest infestation and/or damage

• Informs when control threshold for a pest has been reached

• Helps to assess efficacy of control measures

• Methods based on understanding of crop location behaviour, phenology, immigration behaviours and spatio-temporal distributions 2. Monitor pest density & assess risk

Monitoring methods : Active monitoring

• Count adult pests on plants • Plant beating • Sweep netting - direct 2. Monitor pest density & assess risk

Monitoring methods : Active monitoring

• Count eggs or larval stage pests on/in plants

2. Monitor pest density & assess risk

Monitoring methods : Passive monitoring

• Water traps

• Sticky traps E.g. Pollen beetle monitoring trap Developed through exploitation of understanding of host plant location processes (colour & odour)

2. Monitor pest density & assess risk

Monitoring methods : Developing a monitoring trap for pollen beetle

• Monitoring procedure is time consuming • Pollen beetle immigration occurs over 2-6 week period • Uneven distribution in the field

2. Monitor pest density & assess risk

Monitoring methods : Developing a monitoring trap for pollen beetle colour

2. Monitor pest density & assess risk

Monitoring methods : Developing a monitoring trap for pollen beetle colour

• Electroretinography used to explore the sensitivity of visual receptors • Spectral sensitivity peaks in green region, with additional peaks in blue and UV region

2. Monitor pest density & assess risk

Monitoring methods : Developing a monitoring trap for pollen beetle Volatile lure

• Lure derived from OSR host plant volatiles (in the absence of pheromones)

• 15 electrophysiologically active volatiles identified

2. Monitor pest density & assess risk

Monitoring methods : Developing a monitoring trap for pollen beetle

• In replicated field experiments 2008-2011, Phenylacetaldehyde performed most consistently and was chosen for further development as the lure for the field trap

2. Monitor pest density & assess risk

Monitoring methods : Developing a monitoring trap for pollen beetle

Spring 2013 - Commercially available from Oecos www.oecos.co.uk

http://www.csalomontraps.com/

2. Monitor pest density & assess risk

Monitoring methods : Developing a monitoring trap for pollen beetle

Spring 2013 - Commercially available from Oecos www.oecos.co.uk

Good indication of when beetles

are moving but not currently calibrated to allow threshold determination 2. Monitor pest density & assess risk

Monitoring methods : Developing a monitoring trap for pollen beetle

Trapping experiment 2008-2012

Sticky traps placed upwind and downwind in 178 OSR crops changed 1 or 2/week from green bud – early flowering (~6 weeks)

30m transect conducted at each trap site when traps changed to give mean no. beetles/plant from 10 plants

Sticky traps & transects  trap calibration analysis (& proPlant test) Skellern, Welham, Watts & Cook In Prep Upwind/downwind trap data & environmental info  model for best trap position 2. Monitor pest density & assess risk

Monitoring methods : Developing a monitoring trap for pollen beetle

Trapping experiment 2008-2012

Sticky traps & transects  trap calibration analysis (& proPlant test)

• No simple correlation between no. on trap and no. in crop  Upwind/downwind trap data & environmental info  model for best trap position

• Traps /transects best sited downwind of prevailing wind Skellern, Welham, Watts & Cook In Prep 2. Monitor pest density & assess risk

ProPlantexpert.com on-line risk assessment tool for: Cabbage stem flea beetle, rape stem weevil, pollen beetle, cabbage stem weevil, cabbage seed weevil, brassica pod midge

• proPlant DSS developed in Germany, used widely in Europe • Based on phenological models of pest immigration and life cycle development parameters • Uses local weather conditions (temperature, sunshine h, windspeed & rainfall) • Predicts pest parameters up to 3d in advance • Uses traffic light warning system 2. Monitor pest density & assess risk

ProPlantexpert.com on-line risk assessment tool for: pollen beetle Predicts: start of migration, peaks in migration, end of migration 2. Monitor pest density & assess risk

Validation of proPlant predictions to field data (UK)

2. Monitor pest density & assess risk proPlant can accurately forecast start, peaks (risk periods) and end of immigration; focussing monitoring effort to when it is most needed; reducing unnecessary sprays

Ferguson et al., accepted Pest Management Science 2. Monitor pest density & assess risk

ProPlant tool now available free to UK growers via Bayer CropScience www.bayercropscience.co.uk/

Ferguson et al., accepted Pest Management Science 3. Prevention

Cultural methods e.g. • Crop rotation • Use of pest-resistant cultivars • Habitat diversification : intercropping, cover crops, mixed cropping, trap cropping

Semiochemical e.g. • pheromone repellents

3. Prevention: Use of pest resistant cultivars

Resistant cultivars available for diseases (Light leaf spot, Stem canker)

No commercial cultivars resistant to any insect pest! 3. Prevention: Use of pest resistant cultivars

Exciting genetic breakthrough by Limagrain:

cv. Amelie - resistant to TuYV transmitted by Myzus persicae

• Important IPM tactic ; timely given ban on neonicotinoid seed treatments and resistance in aphids to pyrethroids

3. Prevention: Use of pest resistant cultivars

Exciting genetic breakthrough by Limagrain:

cv. Amelie - resistant to TuYV transmitted by Myzus persicae

• But resistance based on virus not against the host insect • Plant resistance to insect pests still in research pipeline 3. Prevention

Development of preventative methods (and alternative control options) often relies on understanding (then disruption) of host-plant location and selection processes

Visual cues e.g. plant colour

Williams & Cook (2010) in Biocontrol –based IPM of oilseed rape pests 3. Prevention

Development of preventative methods (and alternative control options) often relies on understanding (then disruption) of host-plant location and selection processes

Visual cues e.g. plant colour

Olfactory cues e.g. plant volatiles 3. Prevention

Development of preventative methods (and alternative control options) often relies on understanding (then disruption) of host-plant location and selection processes

Major pests are Crucifer specialists Gustatory cues role of glucosinolates (specific defence compounds found in all Brassicaceae) important?

3. Prevention: Use of pest resistant cultivars

Pollen beetle Visual cues

• Attracted to ‘yellow’; Cultivars with petal colour other than yellow would be less attractive! Cook et al (2013) Arthropod-Plant Interactions 7:249–258

3. Prevention: Use of pest resistant cultivars

Pollen beetle Visual cues

• Attracted to ‘yellow’; Cultivars with petal colour other than yellow would be less attractive! Cook et al (2013) Arthropod-Plant Interactions 7:249–258

3. Prevention: Use of pest resistant cultivars

Pollen beetle Olfactory cues

• Attracted to host plant volatiles including isothiocyanates (breakdown products of glucosinolates)

Alkenyl GS 3-butenyl isothiocyanate Indolyl GS do not catabolise to form stable ITC

low % alkenyl GS high % alkenyl GS high% indolyl GS low % indolyl GS

Cook et al (2006) Ent. Exp. Appl. 119:221-9 3. Prevention: Use of pest resistant cultivars

Pollen beetle Gustatory cues

Hervé et al (2014) J Chem Ecol 40:1220-1231; 2014 APIS 8:383-392

• Intragenotypic variation in feeding damage related to biochemical profile of the bud wall; + relationship with sucrose (no relationship with glucosinolate profile)

• Fewer, smaller eggs laid in genotypes where feeding was reduced 3. Prevention: Use of pest resistant cultivars

Resynthesised lines

• Resynthesized rapeseed lines (B. oleracea × B. rapa ) broaden genetic diversity • Potential as sources of resistance to pest insects e.g. partial resistance to Ceutorhynchs pallidactylus Eickermann et al J. Appl Ent. (2010) 134:542-550; Bull. Ent. Res 101:287-294

3. Prevention: Use of pest resistant cultivars

Hybridization with resistant species

Sinapis alba resistant to attack by Ceutorhynchus obstrictus

B. napus x S. alba  novel resistant lines

Resistance due to glucosinolates profile?

McCaffrey et al. (1999) J. Ag Sci. 132 289-295 Tansey, Dosdall et al (2010) Canadian Entomologist 142:212-221; APIS 4:95-106 3. Prevention: Habitat diversification (intercropping, cover crops, mixed cropping, trap cropping)

Trap crops can act as the ‘pull’ part of push-pull strategies

Push-pull strategies Cook et al., (2007) Ann. Rev. Entomol. 52:375-400

Main crop P U S H Trap crop

Population reduction: P Insecticides U Biological control: biopesticides L natural enemies L 3. Prevention: Habitat diversification (intercropping, cover crops, mixed cropping, trap cropping)

Turnip rape (Brassica rapa) trap crop

More attractive than rapeseed to cabbage stem flea beetle Barari, Cook, Clark & Williams (2005) BioConrol 50: 69-86 Döring, Mennerich & Ulber (2014) Bulletin IOBC/wprs

In field plot experiments, TR borders significantly reduced no. CSFB in rapeseed plots crop vs controls Barari, Cook, Clark & Williams (2005) BioConrol 50: 69-86

3. Prevention: Habitat diversification (intercropping, cover crops, mixed cropping, trap cropping)

Turnip rape (Brassica rapa) trap crop

More attractive than rapeseed for pollen beetles and seed weevils

• early flowering nature • more attractive scent (e.g. phenylacetaldehyde)

Cook et al., 2006; Ent. Exp. Appl. 119:221-9 Cook et al., 2007 Arthropod-Plant Interactions 1:57-67 3. Prevention: Habitat diversification (intercropping, cover crops, mixed cropping, trap cropping)

Replicated field plots

Pollen beetles & seed weevils can be reduced to below spray threshold 3. Prevention: Habitat diversification (intercropping, cover crops, mixed cropping, trap cropping)

… But cost:benefit analysis at full field scale revealed current system NOT currently economically viable for conventional growers (UK)

Cook et al (in prep) 3. Prevention: Habitat diversification (intercropping, cover crops, mixed cropping, trap cropping)

Full field-scale studies in Canada against seedpod weevils Showed trap cropping can be effective…. …in large, square fields but not smaller, narrower fields

Cárcamo , Dosdall et al (2007) Crop Protection 26 :1325–1334 3. Prevention: Use of semiochemicals

• Pheromones • Host plant volatiles (reduced emissions of attractive compounds) • Non-host volatiles

3. Prevention: Use of semiochemicals

• Non-host volatiles as repellents e.g. Lavendula angustifolia Essential oil

Mauchline et al., 2005. Ent. Exp. Appl 114: 181-188. Mauchline, Cook, Powell & Osborne (2013) Ent. Exp. Appl 146:313-320. Mauchline & Cook in prep

4. Control

• Mechanical e.g. trapping

• Botanical insecticides

• Rock dusts

• GM

• RNAi’s

• Conservation biocontrol

• Synthetic insecticide spays as a last resort

4. Control: Mechanical trapping

Potential, but probably not practical due to sheer abundance of pests

http://www.csalomontraps.com/

4. Control: Bio-insecticides

Commercialized

Spinosad insecticide active via contact/ingestion based on chemical compounds found in the bacterial species Saccharopolyspora spinosa

4. Control: Bio-insecticides

In research pipeline

• Entomopathogenic fungi e.g. Metarhizium anisopliae, Beauveria bassiana

• Pathogenic nematodes e.g. Steinernema feltiae

4. Control: Botanical insecticides

Commercialized

Pyrethrum

Research pipeline: Carum carvi Thymus vulgaris Pavela (2011) Industrial Crops and Products 34:888-892

CARE! Many are broad spectrum! 4. Control: via GM

Research pipeline e.g. Protein Inhibitors

Rapeseed with cystein PI oryzacystatinl (OC-I) induced growth inhibition of Myzus Rhabé 2003 Plant Science 164:44-450

- But no effect on cabbage stem flea beetle! Girard et al., (1998) 44:263-270

4. Control: Conservation biocontrol

Use of agronomy & habitat management methods to conserve the natural enemies of crop pests in the agro-environment to improve biocontrol

Delivering CB: Field margins

• Areas of uncropped land, between the arable crop and the boundary (e.g. hedge)

• Activiely managed; sown to annual but usually biannial or perennial plants; 1-6m wide

• Introduced in several countries as part of Agri-environment schemes (EU CAP)

Commercial mixtures for birds, bees/butterflies but none for biocontrol!

4. Control: Conservation biocontrol

Designing field margins for biodiversity & biocontrol across the crop rotation www.rothamsted.ac.uk/field-margins

• Grassy margins support generalist natural enemies of aphids e.g. Holland et al., 2012 Ag. Ecosyt. Env. 155:147-152

4. Control: Conservation biocontrol

Designing field margins for biodiversity & biocontrol across the crop rotation www.rothamsted.ac.uk/field-margins

• Grassy margins support generalist natural enemies of aphids e.g. Holland et al., 2012 Ag. Ecosyt. Env. 155:147-152

• Nectar-rich mixtures can attract other generalists

4. Control: Conservation biocontrol

Designing field margins for biodiversity & biocontrol across the crop rotation www.rothamsted.ac.uk/field-margins

Most efficient natural enemies of the brassica specialist pests of rapeseed are the brassica specialist parasitoids • Parasitism rates up to 80% in untreated crops • Many overwinter as cocoons in soil; susceptible to tillage

• Undisturbed field margins could boost populations

4. Control: Conservation biocontrol

Ceutorhynchus obstrictus 4. Control: Conservation biocontrol

Many commercial margin mixtures do not support brassica- specialist natural enemies! Insect samples & plant composition was monitored from 16 margins sown to 4 different types of semi-natural habitat: (1) wild bird cover (2) florally-enriched grassland (3) insect rich cover (4) natural regeneration

• 9/16 margins contained brassicas: mostly Raphanus sativus, but also R. Raphanistrum, Sinapis alba and Sisymbrium officinale

• 50 parasitoids of rapeseed pests were identified; only 3 were in margins containing no brassicas Brassicas are needed in field margin strips to encourage natural enemies for biocontrol of OSR pests!

4. Control: Conservation biocontrol

Optimizing Brassica ‘banker plants’ for use in field margins for biocontrol across the crop rotation 14 Brassica types screened Brassica napus subsp. Biennis Forage rape best ‘all-rounder’ - Good for parasitoids of:

Pollen beetle

Seed weevil

Pod midge 4. Control: Conservation biocontrol

Do margins containing forage rape improve biocontrol in crops of the rotation? 4. Control: Conservation biocontrol

Do margins containing forage rape improve biocontrol in crops of the rotation?

Margins: Increased biodiversity and biocontrol agents particularly brassica specialists

Crop: Wheat: No significant differences between margin treatments Rapeseed: More spiders and several carabid spp in rapeseed crops next to brassica margins than grass margins

4. Control: Conservation biocontrol

Do margins containing brassicas improve biocontrol in crops of the rotation?

• Abundance of biocontrol agents decreased with distance into the field

• Little evidence of signficant biocontrol effects

• Challenge for future: -move biocontrol agents into the open field - show positive effects on yield

Conclusions

Rapeseed crops are great for invertebrate biodiversity

A large proprtion have functionally useful traits (predators pollinators etc)

For crop pests, IPM tools are available and/or in research pipeline

1. Set action threshold 2. Monitor pest density & assess risk 3. Prevention 4. Control

Further development of ecological approaches to IPM of rapeseed pests will ensure insecticides are used only when necessary; prolonging their active life, safeguarding the environment, maximising profitibility & contributing towards sustainable intensification of the crop

Rothamsted Research where knowledge grows Acknowledgements

Rothamsted Colleagues Project partners John Pickett Ingrid Williams Matthew Skellern Andrew Ferguson Nigel Watts Lesley Smart Christine Woodcock Janet Martin Judith Pell (JK Pell Consulting) Lucy Nevard Thank you for listening!

IOBC Working Group Integrated OILB Control in Oilseed Crops

16th Biannual Meeting September/October 2016, Tartu, ESTONIA

Subgroup Phytopathology [email protected] Gosia Jedryczka

Subgroup Entomology [email protected]

http://wwwuser.gwdg.de/~iobc/index.html Sam Cook

International Organization for Biological and Integrated Control of Noxious Animals and Plants West Palaearctic Regional Section (WPRS) WG ICOC